1. Field of the Invention
The disclosure relates to a power distribution technique, and in particular, to a technique in which power is controlled in a system where a storage battery connected to a renewable energy power generator and a commercial power supply are used in combination.
2. Description of the Related Art
A technique has been recently developed, in which a commercial power supply and a storage battery are used in combination in order to serve as a backup power source for specific electric appliances that should be driven even if power supply is stopped due to power failure of the commercial power supply or to perform peak shaving. On the other hand, a technique for performing a system interconnection operation has also been developed, in which both a renewable energy power generator including a solar cell and a commercial power supply are connected in parallel to supply power to a load from both the commercial power supply and the power generator. Even in such techniques, an inverter for converting the power, generated by a power generator such as a solar cell, into AC power is used.
Additionally, it has been proposed to later install a renewable energy power generator, such as a solar cell, in combination with a technique in which a commercial power supply and a storage battery are used in combination (see Japanese Unexamined Patent Application Publication No. 2001-95179).